Unusual Form situation?

I have form I am working with and trying to add some PHP processing to the form's contents. The form is a html template used by a CGI script. So, instead of having a 'submit' button for the form's content, there is a GIF. The CGI apparently reads the GIF as a button to submit the form's content and move on. How would I go about getting php to recognize this GIF as such? Typically for forms I use: if ($submit) { blah, blah, blah } Would I use if ($gifname)? Would the the GIF's name be the ALT tag? Or am I going to have to sift through the arcane CGI to find some action? Can I make the PHP come to life using the ACTION section of the form (which only refers to the CGI right now)? Thanks, -Mike